Talk:Angel Room

Door Disappearing

After defeating Mom in Depth II, the Angel Room spawned upon the regular door I used to enter the Boss Room. After visiting the Angel Room, the Angel Door disappeared but the regular door isn't back. Hence I can't access the rest of the floor anymore and am forced to go forward to next floor. Have you ever experienced this ? I've search on the BoI reddit, Steam forum etc. and haven't found anything like this. I reckon it is a bug, maybe liked to the fact the Boss Room has doors everywhere during Mom's fight. I'm considering filing a report with my save, but wanted to check here before since I don't have enough experience about the game to be 100% sure. Benspartan (talk) 11:06, 9 December 2014 (UTC)

After the fight with Mom you can never leave to explore the rest of the floor again. --Dooomspeaker (talk) 15:12, 9 December 2014 (UTC)

As simply as it is ! Thanks ! Benspartan (talk) 16:23, 9 December 2014 (UTC)

Statue appears again after killing angel in Afterbirth

I noticed this, not sure if it was a bug or something, the angel room also seemed to stay every time I left, which is a bit weird considering I didn't have Goat's Head nor Belial's Book, is this intended behavior in the update or a bug? --Anon

This was fixed in the latest patch. --Zamie (talk) 02:13, 10 December 2015 (UTC)

Key Pieces and Conquest

I wonder. Do the key pieces obtained from killing Uriel and Gabriel count towards unlocking Conquest? --67.172.166.241 04:33, 4 January 2015 (UTC)

Imagine someone unlocking Mega Satan before Conquest. Wow. You'd have to beat the Chest or Dark Room once. That means killing ???/The Lamb 1 time, Satan/Isaac 7 times, Mom's Heart 17 times, Mom 18 times, and some random assortment of other bosses (5*18+17) times. I mean, you can ignore most of the listed bosses except Mom for this calculation, so truly it's only 6*18+17 (all of the bosses before Mom's Heart) bosses you'd have to beat. That's 125 bosses. You'd have to go through all of those bosses. You'd need to figure out the chance of the devil room paying out with no (tempting) devil deals in order to finish this calculation, and that's not something I really want to try figuring out. Hmm. Yeah, I guess it's possible? If you were really dedicated to getting all the way to the end in the minimum number of runs, it seems possible that you might not qualify for enough angel rooms in order to unlock Conquest. There's also the chance of an Angel Room not dropping an angel room item. Hmm. Anyway, once you've unlocked the key pieces, you'd want to pick up exactly 9 angel room items that are not key pieces, and then see if Conquest unlocks upon picking up a key piece. If you were willing to go through the trouble, I mean. I've got to say, it's a really good question that I can't feel confident answering. It depends on how the game tracks the items picked up in an Angel Room. Does it only recognize items from the angel room pool? I think the key pieces have the distinction of being the only items that can spawn in the angel room that are not part of the angel room pool. You can't reroll an item into a key piece. Does that mean they wouldn't count towards unlocking Conquest? Or, does the game only register "# of items picked up in angel room"? Presumably the only items that can spawn in the angel room are angel room items and the key pieces, so it would make sense that the game doesn't need to specifically check whether the item belongs to the angel room pool because it can reasonably assume that it does. Hmm. Bottom line is that I really don't think it's a question that can be answered well enough without somebody testing something relating to it. Try asking the modders at [their irc channel]. DoomZero [Admin] (talk) 15:31, 4 January 2015 (UTC)

Any pedestal item taken in an Angel Room counts towards Conquest unlock, I tested it. --Anon

Angel Room Generation Chance

I'm confused by one sentence with the new generation chance data of Metarkrai (thanks btw!) :

“

The selection between Angel Room and Devil Room is made on the first teleport/door opening of every floor.

„

Which Exschwasion made clearer, but not in the way I thought it would be :

“

The selection between Angel Room and Devil Room is made at the start of every floor. The chance for the Angel Room to be chosen depends on the previous requirements and can be increased by certain actions, acting as bonuses.

„

If the choice is made at the beginning of the floor, there's is no point seeking the bonuses. Or is it rerolled after beating the boss (if requirements are met)? Or this bonuses are for the next floor (the 10 coin donation explicity says the contrary). Isn't it simply computed once after boos clear ? Benspartan (talk) 09:28, 20 September 2015 (UTC)

I think I misinterpreted the original sentence; I'm guessing it was supposed to mean that the selection is determined upon the first Angel/Devil door opening or the first teleport to the Angel/Devil room of each floor. --Exschwasion (talk) 16:19, 20 September 2015 (UTC)

Bug

It appears that the bug of "Sometimes destroying the rock does not trigger the fight" was added by an anonymous user with no proof. Going to delete it now as I've never heard of this before now. --Zamie (talk) 02:13, 10 December 2015 (UTC)

Angel Room Chances

Is the data added by Metarkrai actually correct? Where did his data come from? This is HenryEx's updated Pastebin for Angel Room generation in Afterbirth, and I'm not immediately seeing how it matches the abstraction of a "strong" and "weak" chance. --Zamie (talk) 15:45, 10 December 2015 (UTC)

I got all the probabilities using a HUD (from HenryEx) displaying the Angel/Devil ratio, and the strong bonus / weak bonus thing came out of it (I just gave it this name because it was easier to mention the mechanics with it). The pastebin is nice, it shows off how the calculations are done, and there was a simple mechanism behind which explains the chances that were seen with extra HUD. Back then, I didn't know there was a bonus/malus for making beggars pay out, which is why I ended up with 2 kinds of bonuses when the pastebin mentions 3 (additional flip with 1/2 chance of success, 1/4 chance of success, 1/10 chance of success). I only happened to know about that recently, and it appears that I messed up something in my notes/calculations, as I didn't see that the bonus from making a Normal Beggar paying out was weaker. (I redid the test and it does as said in the pastebin).

My data is correct, but it's incomplete as it lacks 1 bonus and 1 malus, and as it also lacks (on that page) the new Sacrifice Room bonus. If I understand things right, the new bonus is another coin flip with a 15/50/65% chance for an Angel Room (depending on the "You feel blessed!" blessings) and that is even made when the prerequisites for the other Angel Room coin flips aren't met (seen a Devil Room opening and not paid health for an item). The calculations with this system match the values I have with Missing HUD. (It can't say the order in which this coin flip is made because the order of the coin flips has no influence into the calculations of the success chance.)

Also, the 1/10 coin flips from Normal and Devil Beggar payouts don't cancel each other in terms of probabilities. (ex : With base chance + both payouts, you'll have a 45-4.5 = 40.50% chance to get an Angel Room)(also tested with Missing HUD) So unless HenryEx was speaking of the 1/10 coin flips not being made if both Normal and Devil Beggar paid out, they actually don't cancel each other (but the result is near a cancel).

I wrote a formula using the (Devil ratio without "You feel blessed!") for the Sacrifice Room bonus as it seemed easier to explain than using a 1-(Angel ratio without "You feel blessed!") value, even if the second one is the one that "truly" counts since the game makes coin flips to generate an Angel Room over a default Devil Room.

Thanks for the juicy and interesting information. --Metarkrai (talk) 2:10, 11 December 2015 (UTC)

Can you update this page so that it fully matches the HenryEx pastebin? After that is done, we can go ahead and fix my (incorrect) percentages on the Sacrifice Room page too. --Zamie (talk) 22:02, 13 December 2015 (UTC)

Since the page hasn't been updated yet, here's my proposed rework. It still needs some explanation as to how the series of coin flips works and maybe some examples. --Exschwasion (talk) 21:05, 21 December 2015 (UTC)

Generation Chance

The selection between Angel Room and Devil Room is made upon opening the door after defeating the floor's boss or upon teleporting to the room. The chance for the Angel Room to be chosen depends on the previous requirements and can be modified by certain actions, acting as bonuses.

There is a 50% base chance for the Angel Room to replace the Devil Room, and satisfying certain conditions gives additional chances for the Angel Room to appear:

Condition	Additional Chance
Holding Rosary Bead	50%
Donating 10 coins to the Donation Machine	50%
Holding Key Piece 1	25%
Holding Key Piece 2	25%
Killing a Devil Beggar, Key Master, or Shell Game Beggar Template:Afterbirth Killing a Devil Beggar on the current floor	25%
Donating to a Normal Beggar until it pays out with an item on the current floor	10%
Donating to a Devil Beggar until it pays out with an item on the current floor	-10%
Template:Afterbirth "You feel blessed!" after taking damage 3 times in a Sacrifice Room on the current floor*	15%
Template:Afterbirth "You feel blessed!" after taking damage 5 times in a Sacrifice Room on the current floor*	50%
Template:Afterbirth Both "You feel blessed!" messages on the current floor*	65%

* - Applies even if a devil deal has been taken.

Revamp Talk

Some revisions:

1. There is no mention that the percentage modifiers are multiplicative. For example, if the base chance of 50% and the Rosary Bead gives a 50% chance increase, then it is implied that it is a 100% chance to get an Angel Room, which is not the case.
2. It is implied that the "You feel blessed" effect happens 100% of the time, but this is not the case.

--Zamie (talk) 22:05, 21 December 2015 (UTC)

As Zamie said, each condition gives an additional coin flip (with its own success chance). And if at least one of the coin flip succeeds, an Angel Room appears. (except for the Devil Beggar payout condition that forces a Devil Room over the other coin flips). With base chance and Rosary Bead, you would have a 0.5*0.5 = 0.25 = 25% chance to fail the two coin flips, which means 25% chance to get a Devil Room, and 75% chance to get an Angel Room.

Also, the "You feel blessed!" effect represents a single coin flip, with a variable success chance (depending on the blessings you got from the Sacrifice Room).

I tried writing an explanation for that mechanic too :

Generation chance Bis

The selection between Angel Room and Devil Room is made upon opening the door after defeating the floor's boss or upon teleporting to the room.

The game makes then a series of coin flips to determine if an Angel Room must appear or not. The amount of coin flips done and the success chance of each coin flip is determined by certain actions, mostly counting as bonuses to increase the chance of obtaining an Angel Room.

If one of this coin flips succeeeds, an Angel Room is generated (with a small exception). If all the coin flips fail or no coin flips are done, a Devil Room is generated.

There is a total of 9 coin flips that can be made, the latest one being specific to Afterbirth. The 8 first coin flips all need prerequisites along with a specific condition. If one of the prerequisites isn't verified, these coin flips won't be made even if their specific conditions are met. (holding a Key Piece, holding Rosary Bead,...)

The two prerequisites are :

• Having seen a Devil Room opening. (teleporting and Angel Room do not count)
• Not having paid an item with health. (Devil Deal, Black Market)

The coin flips are as follows :

• 50% chance for an Angel Room.
• 50% chance for an Angel Room if Rosary Bead is held.
• 25% chance for an Angel Room if 10 or more coins were given to the Donation Machine on this floor.
• 25% chance for an Angel Room if Key Piece 1 is held.
• 25% chance for an Angel Room if Key Piece 2 is held.
• 25% chance for an Angel Room if a Devil Beggar, Key Master, or Shell Game Beggar was killed on this floor.
  • Template:Afterbirth Killing Key Masters, Bomb Beggars, and Shell Game Beggars no longer applies the bonus.
• 10% chance for an Angel Room if a Normal Beggar was satisfied on this floor.
  • Template:Afterbirth Making a Key Master, Bomb Beggar, or Shell Game Beggar pay out does not apply the bonus.
• 10% chance for NO Angel Room if a Devil Beggar was satisfied on this floor.
  • If this coin flip suceeds, a Devil Room will be generated regardless of the other coin flips. This coin flip decreases the chances to generate an Angel Room as it needs to fail (90% chance) in order to allow for an Angel Room to be generated.

• Template:Afterbirth 15% or 50% or 65% chance for an Angel Room if "You feel blessed!" fortunes appeared on the Sacrifice Room of this floor.
  • If the first "You feel blessed!" fortune appeared (sacrifice n°3), the chance will be 15%.
  • If the second "You feel blessed!" fortune appeared (sacrifice n°5), the chance will be 50%.
  • If the both "You feel blessed!" fortunes appeared (sacrifices n°3 and n°5), the chance will be 65%.
  • This coin flip doesn't require the prerequisite conditions (having seen a Devil Room opening and not having paid an item with health), which means that it can make an Angel Room spawn before having seen a single Devil Room or after having paid an item with health.

Applied example :

Isaac meets the prerequisites and has Key Piece 1 with him. He beat the Boss Room and a Devil/Angel Room is about to appear.The game will make two coin flips to determine if he gets an Angel Room or not. The first coin flip has a 50% success chance , and the second one a 25% success chance.

Isaac will only get a Devil Room if both coin flips fail, and he will get an Angel Room if one of the coin flips succeeds. The failure chance has then a value of 0.5 * 0.75 = 0.375, which means the success chance has a value of 1 - 0.375 = 0.625. Thus, Isaac has a 62.5% chance to get an Angel Room.

On the next floor, Isaac bombs a Devil Beggar and uses a Joker card. A third coin flip with a 25% success chance will be done with the previous two during the Angel/Devil selection.

The chance to fail all coin flips (and get a Devil Room) become 0.5 * 0.75 * 0.75 = 0.28125, which means that the success chance of the coin flips is approximately 0.72 = 72%. Isaac will have a 72% chance to get an Angel Room on that next floor.

• The highest Angel Room chance is 95.25% in Rebirth and 98.34% in Afterbirth (with the Sacrifice Room blessings).

--Metarkrai (talk) 12:55, 22 December 2015 (UTC)